Motor vehicle suspension systems are configured so that the wheels are able to follow elevational changes in the road surface as the vehicle travels therealong. When a rise in the road surface is encountered, the suspension responds in “jounce” in which the wheel is able to move upwardly relative to the frame of the vehicle. On the other hand, when a dip in the road surface is encountered, the suspension responds in “rebound” in which the wheel is able to move downwardly relative to the integrated body/frame structure of the vehicle. In either jounce or rebound, a spring (i.e., coil, leaf, torsion, etc.) is incorporated with the body structure in order to provide a resilient response to the respective vertical movements of the wheel with regard to the vehicle body structure. However, in order to prevent wheel bouncing and excessive vehicle body motion, a shock absorber or strut is placed at the wheel to dampen wheel and body motion. An example of a MacPherson strut is disclosed in U.S. Pat. No. 5,467,971.
An exemplar a prior art single fastener strut top mount for a MacPherson strut which is manufactured by Adam Opel GmbH, a division of General Motors Company, Detroit, Mich., and is shown generally at 10 in FIG. 1. This prior art strut top mount 10 interfaces with a broad, annular strut tower 12 which at its lower end (not shown) is connected to the body structure of the motor vehicle. This prior art strut top mount 10 features an annular tapered dome 14 that is open downward nestingly within the tower 12, and is welded thereto at a conjoining 16 (the taper being smallest adjacent the conjoining, and largest distant from the conjoining). An annular outer rubber element 18 has an inclined outer surface 18′ which abuts the dome 14. An annular metal insert 20 is preferably provided, for stiffening, within the outer rubber element 18 adjacent the dome 14. An annular stamped metal support shell 22 is adhered to the outer rubber element 18 in nested (i.e., in cross-section being oppositely disposed) relation to the dome 14; and an annular inner rubber element 24 is nested within and adhered to the support shell 22 in cross-section being in opposite disposition with respect to the outer rubber element 18, wherein the aforementioned adherences result from the molding process of the inner and outer rubber elements.
At an annular shelf 22′ of the support shell 22, within an upper polymer housing 26′″, is an upper race 26′ of an annular bearing 26. The lower race 26″ of the bearing 26, within a lower polymer housing 26″″, is located at an annular spring bracket 28, wherein the upper and lower polymer housings mutually have a conventional labyrinthine seal interfacing, and wherein the spring bracket locates and handles loads from both the coil spring 32 and the jounce bumper 34. At an outer periphery 28′ of the spring bracket 28, wherein the spring bracket has a diameter less than that of the strut tower 12, but exceeding the diameter of the dome 14, is formed a spring seat 30 having a rubber insulator 30a upon which abuts the coil spring 32. At an inner periphery 28″ of the spring bracket 28, adjacent the bearing 26, is a connection 28′″ to the jounce bumper 34. A strut shaft 36 is reciprocally interfaced to a strut housing (not shown) in a conventional manner so as to provide damping as it reciprocates in relation thereto in response to jounce and rebound. A tubular metal sleeve 35 receives the strut shaft 36 at a shoulder 36′ thereof, wherein the sleeve is adhered (as a result of the aforementioned molding process) to the inner rubber element 24. At the shoulder 36′ of the strut shaft 36 is a lower washer 38 which abuts a lower end 24′ of the inner rubber element 24 and a lower end of the sleeve 35. Abutting an upper end of the sleeve 35 is an upper washer 40 which also abuts an upper end 24″ of the inner rubber element 24, wherein the upper washer is held in place by a first nut 42 that is threaded onto the strut shaft 36. A retention washer 44 is mounted onto the strut shaft 36, and is held in place between the first nut and a second nut 46, which is also threaded onto the strut shaft. At the periphery of the retention washer 44 is a retention washer rubber element 48.
Spindle length is a metric used in motor vehicle front wheel suspension design, which indicates the distance from the kingpin axis to the wheel center. A minimal value for spindle length is desired for optimal suspension performance, as for example including the known benefits of reduced torque steer and reduced smooth road shake sensitivity. McPherson suspensions are desirable from a cost and mass standpoint, and the ability to minimize the spindle length is most often limited by the need to keep the strut body inboard of the wheel and tire.
Accordingly, what remains needed in the art is a MacPherson strut front wheel suspension having a minimized spindle length which overcomes the inherent packaging limitation imposed by conventional configuring of the strut body with respect to the wheel.